Planar brushless magnetic micromotors

Novel planar magnetic micromotors and microgenerators of active diameter 8 mm were developed, delivering estimated torques of 100 /spl mu/N.m at speeds in excess of 140 000 r/min. Such high performances are due to an innovative use of deep lithography and silicon etching for the fabrication of the stator coils. The hybrid design of the micromotors combines a pair of double-layer three-phase stator coils and a disc-shaped SmCo rotor with eight or 15 axial pairs of poles, all enclosed in a case fabricated using watch-industry micromachining.